Abstract: An entity hole repairing algorithm for three-dimensional closed triangular mesh is presented. From the input of a set of guide points, the upper boundary ring of the hole is searched according to edge features and the position of the objective point. The boundaries of the objective region are recognized on the basis of expanding rings to both two sides through level set method. By sampling on the two rings, a projection method is used and the surrogate surface is constructed. A refined mesh of the triangulated upper ring can be deformed and smoothed by merging the region between the two rings with imported boundary constraint. Then the upper patching surface is created. The inner boundary ring is identified by an inward expansion of the upper ring, and the lower patching surface is created by using the same method. Finally, the repair entity can be constructed by stitching the upper patching surface, lower patching surface, and the region between the upper ring and lower ring. Experiment shows that the algorithm can minimize the manual interaction steps and generate a high-quality scaffold model.

Key words: Boundary ring expansion, Hole repair, Missing entity hole, Patching surface